Transcript Ballistics for the EMS Provider How guns work, what

Ballistics for the EMS Provider
How guns work, what they can do, and how to
treat gun shot wounds
Jeff Brosius,
B.S., NREMT-P, CCEMT-P
Basic Principles of Ballistics

Physics
 Firearm mechanics
 Bullet properties
 Tissue response to force
 Treatment
Basic Principles of Physics

Kinetic Energy is a function of mass and
velocity
 Force is a function of mass and
acceleration/deceleration
 Energy can not be created or destroyed,
only changed from one form to another
Newton’s Laws of Energy

Kinetic Energy = ½ Mass x Velocity²
 Force = mass x G (where G = Gravity Force
 A body in motion will continue in motion
until acted upon by an outside force (tissue,
gravity, friction, solid object, etc.)
Firearm Mechanics

All firearms share some basic principles.
 There is a barrel, which functions to direct
the projectile in a certain direction.
 There is a pin, which causes the powder in
the bullet to ignite.
 There is a trigger, which causes the pin to
strike the bullet.
Firearm Mechanics, cont.

The bullet contains powder, which will burn
rapidly, creating gas vapors.
 These vapors expand inside the barrel,
creating pressure.
 The pressure forces the bullet out of the
barrel.
 The speed of the bullet depends on several
factors (size, friction, etc.)
Bullet Characteristics

Caliber of the bullet (.22, .45, .357, 9mm,
etc.)
 Blunt vs. Hollow vs. Pointed end
 Casing (unjacketed/full metal jacket)
 Density of material
Handguns, by the Numbers
Caliber
Velocity
Muzzle Energy
Energy at 45 feet
Ft/sec
.25
810
73
60
.32
745
140
120
.357
1410
540
475
.38
855
255
255
.40
985
390
365
.44
1470
1150
875
.45
850
370
350
9 mm
935
345
315
Rifles, by the Numbers
Caliber
Velocity
Muzzle Energy
Energy at 300 ft
.22 Hornet
3770
1735
1262
.243
3500
1725
1285
M-16
3650
1185
805
Uzi
1500
440
277 (150 ft)
AK-47
3770
1735
1262
Tissue Response

Cavities – temporary and permanent
– Temporary is larger than the size of the bullet,
and is caused by compression of air around the
projectile.
– Permanent is the destroyed tissue from the
bullet itself.
Cavities

The size of the cavity is not simply a factor
of the bullet size. Other factors are
important, but often unknown
–
–
–
–
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Deflection
Yaw of bullet at impact
Speed of bullet at impact
Angle of impact
Range from gun to target
Cavity Formation
Tissue
Temporary
Cavity
M-16 Rifle Wound
NATO 7.62 Wound
.22 Long Rifle Wound
AK-74 Rifle Wound
.22 cal Hollow Point Wound
Tissue Response

Dense tissue will suffer more damage than
hollow tissue. (Bone vs. lung)
 Elastic tissue will suffer less damage than
rigid tissue. (Muscle vs. liver)
 Strong tissue will withstand damage better.
Treatment Goals

Safety!!!!!!!!!!!!!!!!!!
 ANY penetrating trauma should be treated
with the utmost urgency.
 A small hole on the outside might be hiding
a large hole inside.
 A large hole outside can mask massive
internal damage.
Treatment Goals

ABCs, as always.
 Rapid scene times… grab ‘em and get
moving to the hospital.
 Airway support to include intubation (more
often needed for thorax injuries.)
 Ventilatory support as needed.
 IV enroute, fluids as protocol/Med Control
requests.
Treatment Goals

Hemorrhage control if possible.
 Occlusive dressings for sucking chest
wounds.
 Needle Thoracostomy as needed for tension
pneumothorax.
 Bilateral needle decompression ONLY in an
intubated patient.
Treatment Goals

Early notification of the hospital.
 Constant reassessment…A GSW to the
chest can cause the patient’s condition to
change RAPIDLY. Be vigilant.
 Again, rapid transport is the single best
method for treating a gunshot victim.
 Nothing else will be as helpful as a
physician and hospital trauma care.
Treatment Pitfalls
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Wasting time looking for the bullet or shell casing.
Thinking that a small hole is not a major issue.
Wasting time trying to classify wounds as entrance
or exit.
Closest facility vs. Closest appropriate facility.
Delaying transport for ANY reason, other than
EMS crew safety.
Controversial Issues

Cervical Spine Immobilization.
 Large volumes of fluid replacement.
 Traumatic cardiac arrest treatment.
Pictures of injuries from
firearms….
Acknowledgements
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Andres M. Rubiano, MD
David H Livingston, MD, FACS
Manuel Sotelo, MD
Errington C. Thompson, MD
Eric D. Ladenheim, MD
M.L. Fakler, MD
Grady Memorial Hospital, Atlanta, GA
Emory University School of Medicine,
Department of Surgery
Web Sites

ww.umds.ac.uk
 http://medstat.med.utah.edu
 http://igm.nlm.nih.gov/
 http://www.vnh.org/EWSurg/EWSTOC.html
 http://internet.cybermesa.com/~jbm/ballistics
/calculations.html
 http://www.firearmstactical.com
Web Sites

http://www.iwba.com/
 http://www.milnet.com/milnet/weapons.htm
 http://www.wwa.com/~dvelleux/html
 http://www.vnh.org/EWSurg/EWSTOC.html
Final Words….
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Don’t waste time. What you can’t see will kill the
patient.
Be safe.
Treat the patient.
Do not treat the bullet, and don’t waste time on
details that don’t matter.
Understand that a .22 is just as lethal as a .357.
Don’t waste time.
Questions?